1. Technical Field
This invention generally relates to meta data, and more specifically, to a meta data repository that stores summary information about data.
2. Prior Art
Meta data is information about data. For example, meta data about a particular database might contain descriptions about what type of information is held in each table and field within the database. The databases meta data would also explain the physical attributes of the database such as the types and lengths of the fields, table spacing, indexing, etc. Basically, the meta data repository should be the one place to find out everything and anything about a database.
Meta data catalogs are collections or repositories of meta data. These catalogs are playing an increasingly vital role in publishing authenticated information and in storing and disseminating such information through a controlled but uniform interface. While these catalogs are of substantial use, the normal meta data catalog has several constraints. For instance, these catalogs are inactivexe2x80x94that is, nothing can really be done to the data in the catalogs. Also, these catalogs provide only limited information. The meta data catalog may provide complete information about a particular database, but all the information in that database came from another database, and often a user needs to know more about that other database.
Various attempts have been made to eliminate or alleviate these constraints. A persistent problem, however, is that the catalogs do not hold all the information a user might want. In particular, while a meta data catalog may hold all the physical information of a database, a user is normally not able to determine from the catalog, where the information came fromxe2x80x94that is, the mappings indicating how one database maps to another.
In addition, when several systems are used that all need meta data to function and that all have their own meta data repositories, these repositories must be kept in synchronization with each other. For instance, typically in a data warehouse, extraction programs are used to move data from the operational system to the warehouse, and reporting tools are used to allow business analysts to analyze the warehoused data. Both the extraction programs and the reporting tools have their own meta data; and if a field on one table in the operation system changes, this information must be updated in several places: the warehouse itself, the extraction programs, and the reporting tools.
An object of this invention is to provide an improved meta data catalogue.
Another object of the present invention is to provide a meta data catalog with the ability to drive changes in associated systems.
These and other objective are achieved with a data warehouse, comprising means for database modeling, and means for extracting data from the database and storing the extracted data. A reporting tool is used to make inquiries of the stored data and to format the results of the inquiries, and a single meta data catalog is coupled to the means for modeling, the means for extracting and storing, and the reporting tool. With the preferred embodiment of this invention, a user needs to update information only once. The catalog meta data then drives changes in associated systems, such as a warehouse, extraction programs and reporting tools. In order to accomplish this, the meta data catalog holds enough information to control all these various parts of the process.
The present invention allows a developer to quickly model a new database based on an existing database, identify how the two databases are linked to each other (mapping information), create the database definition, and then use all this captured information in a variety of reporting methods. All the pertinent data are in one location. The meta data catalog is of particular use in very large databases (1000+tables), because much of the functionality included allows changes to the data model to be made quickly and globally when needed.
Further benefits and advantages of the invention will become apparent from a consideration of the following detailed description, given with reference to the accompanying drawing, which specifies and shows a preferred embodiment of the invention.